5813 Costa Rica Miocene — Oi<sson 41 



from Hill No. 3, of the Banana River. Our collection contains 

 several smaller shells from Zone 7, of the Estrella River in 

 which the base is somev^hat more heavily sculptured and with 

 ver}^ fine spirals over the main surface of the whorls. 



Terebra benthalis Dall var. bocasensis, n. var. Plate i, figures 25, 26 



Cf. Terebra {Acus) beni/ialis Dall, 1889, Bull. Mus. Comp. Zool., vol. 

 18, p. 65, pi. 29, fig. 6. 



This species, fairly abundant in the shale beds, just north 

 of the city of Bocas del Toro, Panama, agrees closely with Ball's 

 figure in the Blake Report, except that the revolving series of 

 tubercles in the fossil shells seem to be lower and broader. 

 The whole surface on slight magnification is seen to be finely 

 spirally striated. 



Terebra benthalis was described by Dall from specimens 

 dredged from 100 to 400 fathoms of water off the Morro Light, 

 Havana, Cuba. The species belongs to the section Fusoterebra 

 Sacco. 



Length 27, diameter 6.5 mm. 



Gatun Stage: Bocas del Toro, Pa^Tama. 

 Terebra pumbriensis, n, sp. Plate i, figure 27 



Shell of medium size, composed of 9 whorls (type with a 

 small portion of the apex lost) ; the early post-nuclear whorls 

 (the ist 3 or 4) with two revolving rows of tubercles, formed by 

 the intersection of fine, oblique riblets and two spiral bands; on 

 the 4th whorl of our specimen, a median spiral makes its ap- 

 pearance and rapidly increases in strength so that the later 

 whorls have three rows of tubercles, the upper or most posterior 

 one being somewhat the strongest; the longitudinal ribs are nar- 

 row and oblique, and on the last whorl number about 20; the 

 space between the ribs have three or four fine, incised growth- 

 lines; periphery of the base has an additional tuberculated spiral. 



